US4481084A - Anodization of aluminum electrolyte capacitor foil - Google Patents
Anodization of aluminum electrolyte capacitor foil Download PDFInfo
- Publication number
- US4481084A US4481084A US06/600,239 US60023984A US4481084A US 4481084 A US4481084 A US 4481084A US 60023984 A US60023984 A US 60023984A US 4481084 A US4481084 A US 4481084A
- Authority
- US
- United States
- Prior art keywords
- foil
- process according
- anodization
- electrolyte
- reanodization
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
- H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
- H01G9/0029—Processes of manufacture
- H01G9/0032—Processes of manufacture formation of the dielectric layer
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
- C25D11/02—Anodisation
- C25D11/04—Anodisation of aluminium or alloys based thereon
- C25D11/06—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
- C25D11/02—Anodisation
- C25D11/04—Anodisation of aluminium or alloys based thereon
- C25D11/12—Anodising more than once, e.g. in different baths
Definitions
- This invention relates to the anodization of aluminum electrolytic capacitor foil at low current density to obtain a barrier layer oxide with a high degree of crystallinity and increased capacitance. More particularly it relates to a process carried out at an average current density of 20 ⁇ A/cm 2 to 3 mA/cm 2 of effective surface area in a aqueous solution of a C 4 to C 7 unsubstituted aliphatic dicarboxylic acid containing 0 to 0.05 wt. % of citric or tartaric acid followed by one or more relaxation and reanodization treatments.
- Crystalline barrier layer oxide can be produced by anodizing aluminum in citric, tartaric or boric acid anodizing electrolytes.
- citric acid and tartaric acid are both fairly aggressive acids and will start dissolving the oxide formed.
- Both electrolytes are relatively inefficient anodizing electrolytes and have a slow formation rate, e.g. less than 10 V/min at a current density of 1 mA/cm 2 . This results in a longer anodization time and increased power consumption.
- anodization is carried out in an aqueous electrolyte of C 4 to C 7 unsubstituted aliphatic dicarboxylic acid containing 0 to 0.05 wt. % of citric or tartaric acid at an average current density of 20 ⁇ A/cm 2 to 3 mA/cm 2 of effective surface area.
- the temperature of the electrolyte is 25° C. or above and preferably is 70° C. to 100° C.
- the C 4 to C 7 aliphatic dicarboxylic acid is the main electrolyte and is chosen for its anodization efficiency, e.g. an anodization rate of greater than 20V/min at a current density of 1 mA/cm 2 . It should not be aggressive with respect to aluminum and its anodic oxide and is preferably adipic, glutaric, succinic, or pimelic acid. Its concentration should be 0.1 to 6 wt. %, and preferably 3 wt. %, of the aqueous solution. Mixtures of the C 4 to C 7 aliphatic dicarboxylic acids are also effective; their total concentration should be 0.1 to 6 wt. %, and preferably 3 wt. %, of the aqueous solution.
- the pH of the electrolyte is adjusted to a value of between 4 and 8, and preferably 6, by a basic reagent, e.g., with ammonium hydroxide. It is desirable to keep the pH within this range, that is around neutral, so the solution will not attack the foil or oxide as it will under more acidic and more basic conditions.
- the preferred electrolyte temperature during the anodization should be between 70° C. and just under the boiling point, e.g., 98° C. and is most preferably 85° C.
- the C 4 to C 7 acids are the preferred acids of the known C 2 to C 1O anodizing acids.
- the C 2 and C 3 acids (oxalic and malonic) have high first dissociation constants and are too aggressive for use on etched foil.
- the C 8 to C 10 acids are not as readily available and are more expensive than the C 4 to C 7 acids which are therefore the preferred ones for practical reasons.
- the low current density promotes crystalline oxide formation during anodization in aqueous solutions of the above acids.
- the low current density can be obtained practically by using more than one power source during anodization.
- the current density is proportional to the formation voltage divided by the resistance of the system times an exponential factor which is essentially constant for a given system. By dividing the formation voltage among multiple power supplies, the desired average current density can be obtained. Alternatively, the length of the anodization zone may be increased to reduce the average current density.
- the preferred current density range is 20 ⁇ A/cm 2 to 3 mA/cm 2 of the effective surface area to promote crystalline oxide formation.
- citric or tartaric acid helps to promote crystalline oxide formation during anodization
- the chief contribution of the additive is to decrease the relaxation time of the anodized film.
- Both citric and tartaric acids are aggressive and, as anodization proceeds, tend to dissolve the oxide which is formed. For this reason the amount of either is kept as low as possible to promote crystalline oxide formation while keeping dissolution low so that only amorphous oxide, which is preferentially attacked, is dissolved. It was found that concentrations of 0.005 to 0.05 wt. %, and preferably 0.01 wt. % meet these conditions.
- a high degree of crystallinity is desirable as it is associated with a thinner barrier layer oxide and higher capacitance.
- Parameters that favor crystalline oxide formation, along with anodization at low current densities, are high electrolyte temperature and high formation voltage.
- the presence of crystalline anodic oxide can be confirmed by transmission electron diffraction patterns of the isolated anodic oxide film. The size, shape, and distribution of the crystals can be observed in transmission electron micrographs.
- the barrier layer oxide must be relaxed and reanodized to stabilize it.
- Ease of relaxation has been found to depend upon the anodization (formation) voltage, current density, and the electrolyte composition and temperature. For a given electrolyte and a low current density, a high anodization voltage and a high electrolyte temperature result in a more crystalline oxide and a thinner amorphous layer. The less amorphous material is present, the easier the relaxation process is. The presence of the small amount of citric or tartaric acid in the anodization electrolyte dissolves some of this amorphous oxide and reduces its thickness leading to easier relaxation.
- thermal relaxation is not as effective as is the presence of citric or tartaric acid in the electrolyte.
- foils anodized to less than approximately 150V by the present process, even with the citric or tartaric acid addition in the electrolyte require thermal relaxation also.
- one or more relaxation steps may be required. After complete relaxation and reanodization the foil is stabilized.
- the thermal relaxation is carried out between 400° C. and 550° C. If a film is relaxed, there will be a current flow during reanodization. When thermal relaxation is carried out below 400° C., there is minimal relaxation as shown by little, if any, current flow during reanodization. When the thermal relaxation is carried out above 550° C., there is a large current flow during reanodization, but leakage current increases after reanodization which is an indication that the oxide film has been damaged.
- formation of crystalline oxide can be increased during anodization in an efficient anodization electrolyte by carrying out the anodization at a current density of at most 3 mA/cm 2 of effective surface area, and preferably at an electrolyte temperature above 70° C.
- the foil is relaxed in air or by one or more thermal treatments between 400° and 550° C. After the foil is reanodized to heal any defects in the barrier layer oxide, no further instability will occur.
- a standard phosphate electrolyte is preferably an aqueous solution of ammonium or sodium dihydrogen phosphate and confers hydration resistance to the anodized foil.
- the foil may be pretreated before anodization by a thermal oxidation step. This pretreatment further increases the anodization efficiency, the degree of crystallinity and the capacitance.
- an estimated percent crystalline oxide content of the barrier layer oxide is presented.
- a series of barrier layer oxide films were treated with a standard phosphoric-chromic acid stripping solution which preferentially dissolves amorphous oxide.
- the amount of crystalline oxide remaining was measured with a microprobe.
- the capacitance of the original sample was graphed versus the measured crystallinity of the sample to obtain a curve of capacitance vs percent crystalline oxide.
- the estimated percent crystalline oxide values below were obtained by measuring the capacitance and obtaining the corresponding crystalline oxide content from the curve.
- Electro-polished foil was anodized in a 3% glutaric acid electrolyte at pH 6 180V at a current density of 1 mA/cm 2 over a temperature range of 20° C. to 92° C.
- the results, together with the estimated percent crystalline oxide, are shown in the table below.
- Electro-polished foil was anodized to 180V at 80° C. in 3 wt. % adipic or glutaric acid, both at pH 6. Capacitance is in 10 -2 ⁇ F/cm 2 and current density is in mA/cm 2
- Electrolyte A is 3 wt. % adipic acid
- electrolyte B is 3 wt. % adipic acid plus 0.1 wt. % citric acid. Both electrolytes were at pH 6 and electro-polished foil was anodized to the following voltages at 85° C. and 3 mA/cm 2 .
- a mixture of 1.5% adipic acid, 1.5% glutaric acid and 0.005% citric acid at pH6 was used at 90° C. to anodize electro-polished foil at 1 mA/cm 2 to 180V
- the capacitance was 4.60 10 -2 ⁇ F/cm 2 and the estimated crystallinity was 73%.
- the addition of the citric acid did increase the amount of crystalline oxide formed; subsequent experiments on etched foil showed a similar increase but that the citric or tartaric acid concentration should not exceed 0.05 wt. %.
- the major effect of the acids is to promote ease of relaxation as shown in the next example.
- the barrier layer oxides formed in glutaric acid (Example 2) at 1 mA/cm 2 and 0.1 mA/cm 2 were 60% and 86% crystalline, respectively. They required approximately 72 hrs and 20 hrs, respectively, to relax in air. However, when a small amount of citric acid (0.005 to 0.01 wt. %) was added to the adipic acid, glutaric acid, or the mixed adipic-glutaric acid electrolyte, the barrier layer oxide relaxed immediately in air even when the current density was 3 mA/cm 2 (approximately 50% crystalline oxide content).
- citric acid or alternately tartaric acid, dissolves some of the amorphous oxide during the anodization process, thinning it, and allowing the resulting barrier layer oxide to relax more easily.
- AC etched capacitor foil was anodized in 3% adipic acid at pH 6 and a current density of less than 0.1 mA/cm 2 to 150V.
- One sample was thermally pretreated before anodization and one was not pretreated.
- the untreated foil had a capacitance of 10.80 ⁇ F/in 2 and was 50% crystalline, while the treated foil had a capacitance of 13.12 ⁇ F/in 2 and was 80% crystalline.
- crystalline oxide content of barrier layer oxide for electrolytic capacitor use can be increased by carrying out the anodization in an efficient anodization electrolyte containing 0 to 0.05 wt. % citric or tartaric acid by carrying out the process at current densities between 20 ⁇ A/cm 2 and 3 mA/cm 2 .
- Anodization temperature is preferable 70° to 100° C., and most preferably 85° C.
- Electrolyte pH should be between 4 and 8 and preferably is 6.
Abstract
Description
TABLE 1 ______________________________________ Sample Formation Capacitance Est. Percent Number Temperature (10.sup.-2 μF/cm.sup.2) Crystallinity ______________________________________ 1 20° C. 3.23 <10% 2 25° C. 3.14 <10% 3 30° C. 3.16 <10% 4 35° C. 3.15 <10% 5 40° C. 3.23 <10% 6 45° C. 3.28 13% 7 50° C. 3.40 18% 8 55° C. 3.47 21% 9 60° C. 3.65 30% 10 65° C. 3.78 36% 11 70° C. 3.94 43% 12 75° C. 4.16 53% 13 80° C. 4.37 63% 14 85° C. 4.44 66% 15 92° C. 4.67 76% ______________________________________
TABLE 2 ______________________________________ Current Density Electrolyte 3.0 1.2 0.6 0.3 0.1 ______________________________________ Adipic Acid Cap. 4.18 4.43 4.53 4.75 4.93 % Cryst. 53 65 70 80 88 Glutaric Acid Cap. 4.08 4.34 4.55 4.75 4.89 % Cryst. 49 61 71 80 86 ______________________________________
TABLE 3 ______________________________________ Voltage 60 120 180 ______________________________________ A, Capacitance 10.38 6.33 4.54 % Cryst. 34 61 70 B, Capacitance 11.63 6.63 4.86 % Cryst. 55 70 85 ______________________________________
Claims (13)
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US06/600,239 US4481084A (en) | 1984-04-16 | 1984-04-16 | Anodization of aluminum electrolyte capacitor foil |
CA000477976A CA1252062A (en) | 1984-04-16 | 1985-03-29 | Anodization of aluminum electrolytic capacitor foil |
GB08508974A GB2157710B (en) | 1984-04-16 | 1985-04-04 | Anodizing aluminium capacitor foil |
JP60079472A JPS60234310A (en) | 1984-04-16 | 1985-04-16 | Method of increasing capacitance of anode oxide aluminum electrolytic condenser foil |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US06/600,239 US4481084A (en) | 1984-04-16 | 1984-04-16 | Anodization of aluminum electrolyte capacitor foil |
Publications (1)
Publication Number | Publication Date |
---|---|
US4481084A true US4481084A (en) | 1984-11-06 |
Family
ID=24402836
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US06/600,239 Expired - Fee Related US4481084A (en) | 1984-04-16 | 1984-04-16 | Anodization of aluminum electrolyte capacitor foil |
Country Status (4)
Country | Link |
---|---|
US (1) | US4481084A (en) |
JP (1) | JPS60234310A (en) |
CA (1) | CA1252062A (en) |
GB (1) | GB2157710B (en) |
Cited By (28)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4582574A (en) * | 1985-08-15 | 1986-04-15 | Sprague Electric Company | Preparation of capacitor electrodes |
US4589959A (en) * | 1983-12-27 | 1986-05-20 | Permelec Electrode Ltd. | Process for electrolytic treatment of metal by liquid power feeding |
US5078845A (en) * | 1988-08-24 | 1992-01-07 | Matsushita Electric Industrial Co., Ltd. | Process for preparing an electrode foil for use in aluminum electrolytic capacitors |
US5143591A (en) * | 1991-06-11 | 1992-09-01 | U.S. Philips Corporation | Method of producing ultra stable aluminum oxide for high volt electrolytic capacitors and product thereof |
US5158663A (en) * | 1991-08-12 | 1992-10-27 | Joseph Yahalom | Protective coatings for metal parts to be used at high temperatures |
WO1993003207A1 (en) * | 1991-07-30 | 1993-02-18 | Minsky Radiotekhnichesky Institut | Method for making metal sublayer based on aluminium or its alloys |
US5382347A (en) * | 1991-08-18 | 1995-01-17 | Yahalom; Joseph | Protective coatings for metal parts to be used at high temperatures |
US5643432A (en) * | 1995-07-13 | 1997-07-01 | Avx Corporation | Selective anodization of capacitor anode body |
US6197184B1 (en) | 1998-10-29 | 2001-03-06 | Pacesetter, Inc. | Method of producing high quality oxide for electrolytic capacitors |
US6242111B1 (en) * | 1992-09-17 | 2001-06-05 | Applied Materials, Inc. | Anodized aluminum susceptor for forming integrated circuit structures and method of making anodized aluminum susceptor |
US6404615B1 (en) | 2000-02-16 | 2002-06-11 | Intarsia Corporation | Thin film capacitors |
US6475368B2 (en) | 2001-03-07 | 2002-11-05 | Kemet Electronics Corporation | Method of aqueous anodizing aluminum substrates of solid capacitors |
US6486530B1 (en) | 2000-10-16 | 2002-11-26 | Intarsia Corporation | Integration of anodized metal capacitors and high temperature deposition capacitors |
US6548324B2 (en) | 2001-06-06 | 2003-04-15 | Kemet Electronics Corporation | Edge formation process without anodizing for aluminum solid electrolytic capacitor |
US6562652B2 (en) | 2001-06-06 | 2003-05-13 | Kemet Electronics Corporation | Edge formation process with anodizing for aluminum solid electrolytic capacitor |
US20040140221A1 (en) * | 2003-01-21 | 2004-07-22 | Kinard John Tony | Method of anodizing aluminum utilizing stabilized silicate solutions |
US20040182717A1 (en) * | 2003-03-17 | 2004-09-23 | Kinard John Tony | Capacitor containing aluminum anode foil anodized in low water content glycerine-phosphate electrolyte without a pre-anodizing hydration step |
US7452473B1 (en) | 2003-10-06 | 2008-11-18 | Pacesetter, Inc. | Laser marking of raw aluminum anode foil to induce uniform patterning etching |
US20090038946A1 (en) * | 2005-06-17 | 2009-02-12 | Tohoku University | Metal oxide film, laminate, metal member and process for producing the same |
CN102839408A (en) * | 2012-08-10 | 2012-12-26 | 常州大学 | Method for preparing porous aluminum oxide film with super-large hole pitch through ultrasonic auxiliary anode oxidation |
CN103014808A (en) * | 2012-12-14 | 2013-04-03 | 中国计量学院 | Method for preparing aluminum alloy anodic oxidation film by tartaric acid anodic oxidation |
CN104195614A (en) * | 2014-09-19 | 2014-12-10 | 南通市滨海装饰材料有限公司 | Passivator and aluminum alloy pre-treatment technology |
US9852849B2 (en) | 2016-05-27 | 2017-12-26 | Pacesetter, Inc. | Using etch resist patterns and formation for facilitation of laser cutting, particle and leakage current reduction |
US9969030B2 (en) | 2016-05-12 | 2018-05-15 | Pacesetter, Inc. | Laser drilling of metal foils for assembly in an electrolytic capacitor |
US9978529B2 (en) | 2016-01-11 | 2018-05-22 | Pacesetter, Inc. | Oxide on edges of metal anode foils |
US10090112B2 (en) | 2016-01-15 | 2018-10-02 | Pacesetter, Inc. | Use of etch resist masked anode frame for facilitation of laser cutting, particle and leakage current reduction |
CN110016702A (en) * | 2019-04-18 | 2019-07-16 | 宜都东阳光化成箔有限公司 | A kind of aluminium electrolutic capacitor super-pressure Waste Acid From Hua Cheng Foil chemical synthesis technology |
DE102022104622A1 (en) | 2022-02-25 | 2023-08-31 | Tdk Electronics Ag | Hybrid polymer capacitor |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0782968B2 (en) * | 1988-08-03 | 1995-09-06 | 信英通信工業株式会社 | Method for manufacturing electrode foil for aluminum electrolytic capacitor |
JP4653687B2 (en) * | 2006-03-31 | 2011-03-16 | ニチコン株式会社 | Method for producing electrode foil for electrolytic capacitor |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4113579A (en) * | 1977-04-28 | 1978-09-12 | Sprague Electric Company | Process for producing an aluminum electrolytic capacitor having a stable oxide film |
US4437945A (en) * | 1983-08-31 | 1984-03-20 | Sprague Electric Company | Process for anodizing aluminum foil |
US4437946A (en) * | 1983-08-31 | 1984-03-20 | Sprague Electric Company | Stabilization of aluminum electrolytic capacitor foil |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
AT309942B (en) * | 1971-05-18 | 1973-09-10 | Isovolta | Process for anodic oxidation of objects made of aluminum or its alloys |
-
1984
- 1984-04-16 US US06/600,239 patent/US4481084A/en not_active Expired - Fee Related
-
1985
- 1985-03-29 CA CA000477976A patent/CA1252062A/en not_active Expired
- 1985-04-04 GB GB08508974A patent/GB2157710B/en not_active Expired
- 1985-04-16 JP JP60079472A patent/JPS60234310A/en active Pending
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4113579A (en) * | 1977-04-28 | 1978-09-12 | Sprague Electric Company | Process for producing an aluminum electrolytic capacitor having a stable oxide film |
US4437945A (en) * | 1983-08-31 | 1984-03-20 | Sprague Electric Company | Process for anodizing aluminum foil |
US4437946A (en) * | 1983-08-31 | 1984-03-20 | Sprague Electric Company | Stabilization of aluminum electrolytic capacitor foil |
Cited By (50)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4589959A (en) * | 1983-12-27 | 1986-05-20 | Permelec Electrode Ltd. | Process for electrolytic treatment of metal by liquid power feeding |
GB2179059A (en) * | 1985-08-15 | 1987-02-25 | Sprague Electric Co | Preparation of aluminium foil capacitor electrodes |
GB2179059B (en) * | 1985-08-15 | 1989-08-16 | Sprague Electric Co | Preparation of aluminium foil capacitor electrodes |
US4582574A (en) * | 1985-08-15 | 1986-04-15 | Sprague Electric Company | Preparation of capacitor electrodes |
US5078845A (en) * | 1988-08-24 | 1992-01-07 | Matsushita Electric Industrial Co., Ltd. | Process for preparing an electrode foil for use in aluminum electrolytic capacitors |
US5143591A (en) * | 1991-06-11 | 1992-09-01 | U.S. Philips Corporation | Method of producing ultra stable aluminum oxide for high volt electrolytic capacitors and product thereof |
WO1993003207A1 (en) * | 1991-07-30 | 1993-02-18 | Minsky Radiotekhnichesky Institut | Method for making metal sublayer based on aluminium or its alloys |
US5158663A (en) * | 1991-08-12 | 1992-10-27 | Joseph Yahalom | Protective coatings for metal parts to be used at high temperatures |
US5382347A (en) * | 1991-08-18 | 1995-01-17 | Yahalom; Joseph | Protective coatings for metal parts to be used at high temperatures |
US6242111B1 (en) * | 1992-09-17 | 2001-06-05 | Applied Materials, Inc. | Anodized aluminum susceptor for forming integrated circuit structures and method of making anodized aluminum susceptor |
US5643432A (en) * | 1995-07-13 | 1997-07-01 | Avx Corporation | Selective anodization of capacitor anode body |
US6197184B1 (en) | 1998-10-29 | 2001-03-06 | Pacesetter, Inc. | Method of producing high quality oxide for electrolytic capacitors |
US6404615B1 (en) | 2000-02-16 | 2002-06-11 | Intarsia Corporation | Thin film capacitors |
US6486530B1 (en) | 2000-10-16 | 2002-11-26 | Intarsia Corporation | Integration of anodized metal capacitors and high temperature deposition capacitors |
US6475368B2 (en) | 2001-03-07 | 2002-11-05 | Kemet Electronics Corporation | Method of aqueous anodizing aluminum substrates of solid capacitors |
US6548324B2 (en) | 2001-06-06 | 2003-04-15 | Kemet Electronics Corporation | Edge formation process without anodizing for aluminum solid electrolytic capacitor |
US6562652B2 (en) | 2001-06-06 | 2003-05-13 | Kemet Electronics Corporation | Edge formation process with anodizing for aluminum solid electrolytic capacitor |
US20030160290A1 (en) * | 2001-06-06 | 2003-08-28 | Kemet Electronics Corporation | Edge formation process for aluminum solid electrolytic capacitor |
US6707663B2 (en) * | 2001-06-06 | 2004-03-16 | Kemet Electronics Corporation | Edge formation process for aluminum solid electrolytic capacitor |
US6744621B2 (en) | 2001-06-06 | 2004-06-01 | Kemet Electronics Corporation | Edge formation process for aluminum solid electrolytic capacitor |
US20040140221A1 (en) * | 2003-01-21 | 2004-07-22 | Kinard John Tony | Method of anodizing aluminum utilizing stabilized silicate solutions |
US20080280153A1 (en) * | 2003-01-21 | 2008-11-13 | John Tony Kinard | Method of Anodizing Aluminum Utilizing Stabilized Silicate Solutions |
US20050103640A1 (en) * | 2003-01-21 | 2005-05-19 | Kinard John T. | Method of anodizing aluminum utilizing stabilized silicate solutions |
US20050211565A1 (en) * | 2003-03-17 | 2005-09-29 | Kinard John T | Capacitor containing aluminum anode foil anodized in low water content glycerine-phosphate electrolyte without a pre-anodizing hydration step |
US20040188269A1 (en) * | 2003-03-17 | 2004-09-30 | Harrington Albert Kennedy | Capacitor containing aluminum anode foil anodized in low water content glycerine-phosphate electrolyte |
US20060124465A1 (en) * | 2003-03-17 | 2006-06-15 | Harrington Albert K | Capacitor containing aluminum anode foil anodized in low water content glycerine-phosphate electrolyte |
US7125610B2 (en) | 2003-03-17 | 2006-10-24 | Kemet Electronics Corporation | Capacitor containing aluminum anode foil anodized in low water content glycerine-phosphate electrolyte without a pre-anodizing hydration step |
US7342773B2 (en) | 2003-03-17 | 2008-03-11 | Kemet Electronics Corporation | Capacitor containing aluminum anode foil anodized in low water content glycerine-phosphate electrolyte |
US20040182717A1 (en) * | 2003-03-17 | 2004-09-23 | Kinard John Tony | Capacitor containing aluminum anode foil anodized in low water content glycerine-phosphate electrolyte without a pre-anodizing hydration step |
US7780835B2 (en) | 2003-03-17 | 2010-08-24 | Kemet Electronics Corporation | Method of making a capacitor by anodizing aluminum foil in a glycerine-phosphate electrolyte without a pre-anodizing hydration step |
US7452473B1 (en) | 2003-10-06 | 2008-11-18 | Pacesetter, Inc. | Laser marking of raw aluminum anode foil to induce uniform patterning etching |
US20090038946A1 (en) * | 2005-06-17 | 2009-02-12 | Tohoku University | Metal oxide film, laminate, metal member and process for producing the same |
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CN103014808B (en) * | 2012-12-14 | 2015-07-29 | 中国计量学院 | The method of aluminium alloy anode oxide film is prepared with tartrate anodic oxidation |
CN103014808A (en) * | 2012-12-14 | 2013-04-03 | 中国计量学院 | Method for preparing aluminum alloy anodic oxidation film by tartaric acid anodic oxidation |
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US11469052B2 (en) | 2016-01-11 | 2022-10-11 | Pacesetter, Inc. | Oxide on edges of metal anode foils |
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US9969030B2 (en) | 2016-05-12 | 2018-05-15 | Pacesetter, Inc. | Laser drilling of metal foils for assembly in an electrolytic capacitor |
US11185948B2 (en) | 2016-05-12 | 2021-11-30 | Pacesetter, Inc. | Laser drilling of metal foils for assembly in an electrolytic capacitor |
US9852849B2 (en) | 2016-05-27 | 2017-12-26 | Pacesetter, Inc. | Using etch resist patterns and formation for facilitation of laser cutting, particle and leakage current reduction |
CN110016702B (en) * | 2019-04-18 | 2020-12-11 | 内蒙古乌兰察布东阳光化成箔有限公司 | Ultrahigh-voltage foil formation process for aluminum electrolytic capacitor |
CN110016702A (en) * | 2019-04-18 | 2019-07-16 | 宜都东阳光化成箔有限公司 | A kind of aluminium electrolutic capacitor super-pressure Waste Acid From Hua Cheng Foil chemical synthesis technology |
DE102022104622A1 (en) | 2022-02-25 | 2023-08-31 | Tdk Electronics Ag | Hybrid polymer capacitor |
Also Published As
Publication number | Publication date |
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JPS60234310A (en) | 1985-11-21 |
GB8508974D0 (en) | 1985-05-09 |
GB2157710A (en) | 1985-10-30 |
GB2157710B (en) | 1987-09-09 |
CA1252062A (en) | 1989-04-04 |
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